Mapping Text to Enum entries

private bool GetEnumValues(Type enumType, object value, out IEnumerable<object> enumValues)
{
  bool enumCompletelyCovered = false;
  List<object> enumValueCollection = new List<object>();

  // perform a shortcut comparison for the common case
  if(Enum.IsDefined(enumType, value))
  {
    // the specified value completely matches an enumeration entry
    enumValueCollection.Add(value);
    enumCompletelyCovered = true;
  }
  else
  {
    // attempt to decompose the specified value into several enumeration entries
    // compare enumeration values as the largest comparable type (UInt64)
    ulong currentEnumValue = Convert.ToUInt64(value);

    // get an array of all the possible enumeration entries
    Array values = Enum.GetValues(enumType);

    // process the enumeration entries in reverse order to compare the largest values first
    int index = values.Length - 1;
    while(index >= 0)
    {
      // convert currently indexed enumeration entry value to a comparable type
      ulong currentIndexedValue = System.Convert.ToUInt64(values.GetValue(index));

      // special case the None enumeration
      if((index == 0) && (currentIndexedValue == 0L))
      {
        break;
      }

      // use a bit-field comparison technique
      if((currentEnumValue & currentIndexedValue) == currentIndexedValue)
      {
        currentEnumValue -= currentIndexedValue;
        enumValueCollection.Add(values.GetValue(index));
      }

      // move to the next up enumeration entry
      index--;
    }

    // special case the None enumeration
    // Add the assumed None enumeration if:
    //  the enumeration value collection is empty;
    //  and the current value is 0;
    //  and the current enumeration entry is the first entry;
    //  and the current enumeration entry matches the current value.
    if((enumValueCollection.Count == 0) && (currentEnumValue == 0L) && (index == 0) && (System.Convert.ToUInt64(values.GetValue(index)) == 0L))
    {
      enumValueCollection.Add(values.GetValue(index));
    }

    // reverse the enumeration value collection to go from least to greatest values
    enumValueCollection.Reverse();

    // the enumeration was completely covered if the current value is 0 and there is at lease one entry in the enumeration value collection
    enumCompletelyCovered = (currentEnumValue == 0L) && (enumValueCollection.Count > 0);
  }

  enumValues = enumValueCollection;
  return enumCompletelyCovered;
}